Single function emergency switches are well known for use with land and marine vehicles. The switches are used in many cases only to disconnect power when the vehicle operator accidently leaves the vehicle. In such cases, the operator may be unable to communicate to others for assistance or of his difficulties. If the operator is in the water he may be hit by other boats or his boat may be rammed if the boat lights are not on or other signals displayed.
Various types of lightweight, open vehicles, such as snowmobiles, dune buggies and the like are used in rather rugged, often hilly, wooded terrain where hidden obstacles are frequent. Because of this fact and the rather carefree way in which these vehicles tend to be used, spills and other accidents frequently occur. In the event of an accident, the operator is likely to be thrown from the vehicle, with the motor running and in gear. It is obvious that the fact that the motor is running and the vehicle under power creates an added unnecessary safety hazard, both to the operator and to persons in the neighborhood. Even if no one is injured, the vehicle is liable to be seriously damaged or at least to run some distance before it comes to a stop.
The fact that the operator is no longer holding the throttle open doesn't materially diminish the problem as the vehicle can run an appreciable distance when in gear, especially if the engine has a high idle speed or if it is choked as may be the case in cold water. Moreover, carburetor icing in cold damp weather can freeze the throttle in an open position after a long run at a steady speed, allowing the vehicle to continue on out of control after an accident.
Another example of a kind of hazard which the invention will alleviate occurs because many lightweight vehicles do not have a clutch and start moving as soon as the brake is released. This tends to produce "jerk" starts which may throw an unwary operator backwards with the result that he loses control of the vehicle, which may run into something before the operator recovers.
Other examples of extremely hazardous situations which are created by small power tools, lawnmowers, tractors, and the like when an operated loses control will occur to anyone having experience with that kind of equipment.
U.S. Pat. No. 3,210,494 to Murdock, which is herein incorporated by reference, discloses an emergency cut off device for an engine of a vehicle which contains a contact establishing means between a circuit disabling position, a circuit closing position and a reset position. The contact establishing means disables the operation of the engine when the operator has moved away a predetermined distance.
U.S. Pat. No. 3,654,411 to Wohnlich et al disclose a breakaway switch for a trailer that is intended to activate an electrical circuit to apply the trailer brakes or give a signal upon separation of the trailer from the towing vehicle.
U.S. Pat. No. 3,726,264 to Lariviere, which is herein incorporated by reference, discloses a safety stopping device for marine vehicles and employs a cord connected at one end to the pilot of the boat and at its other end to the safety device for the grounding of the ignition circuit of the engine either by operating a push button or by ripping off the cord held between the push button and a retaining head traversing the button. There is provided a stem which is capable by axial movement to connect two fixed contact terminals interposed in the ignition switch.
Besides being monofunctional, the prior art switches are known to corrode when used in wet environments especially when sea water is retained within the switch over a period of time.